Technical Field
The present disclosure relates to the field of power control, and in particular to a method and circuit for dynamic power control in a data processing pipeline.
Description of the Related Art
In synchronous data processing pipelines, each stage in the pipeline performs its corresponding operation on each significant edge of the clock signal, causing data to propagate through the pipeline. An advantage of such synchronous pipelines is that they allow relatively high data processing rates, as this rate is only limited by the data processing time of each stage and not by the overall propagation delay of the pipeline. However, such a synchronous operation can have drawbacks in certain applications.
For example, in the field of NFC (near-field communications), an RF card is powered by the RF field generated by the NFC reader, and modulates the RF field in order to transmit data back to the reader. If the RF field is weak, the RF card may reduce its clock rate in order to reduce its power consumption. However, the current consumption of data processing pipelines within the RF card will have current consumption peaks occurring on each significant clock edge, and at low frequencies, it may not be possible to smooth these peaks. This can lead to the current consumption of the RF card being visible at the card antenna, which may disrupt communication between the card and the reader.
Furthermore, side channel attacks against secure devices such as encryption or decryption circuits use powerful correlation techniques based on power consumption to try to determine the data being processed by the data processing pipeline. Synchronous pipelines do not provide sufficient protection against such attacks.
The subject matter discussed in the Background section is not necessarily prior art and should not be assumed to be prior art merely as a result of its discussion in the Background section. Along these lines, the recognition of one or more problems in the prior art discussed in the Background section and the subject matter associated therewith should not be treated as prior art unless expressly stated to be prior art. Instead, the discussion in the Background section encompassing one or more recognized problems in the prior art should be treated as part of the inventor's approach to the particular problem, which in and of itself may also be inventive.